South Korea has identified “a probability” that Russia will help North Korea enhance its nuclear weapons program in the course of the burgeoning partnership between Moscow and Pyongyang.

“Russia’s use of the DPRK’s weapons are direct violations of multiple Security Council resolutions,” South Korean Ambassador Hwang Joon-kook said at a U.N. Security Council forum in New York on Monday. “What is more problematic for us is a probability that [the] DPRK may receive, in return from Russia, something important for its military capabilities — in particular, nuclear and missile-related technologies.”